The American trainer said this will force Marquez to leave his counterpunching style and engage Pacquiao in a toe-to-toe battle, and thus make the Mexican a more vulnerable target for the Filipino.

"Marquez will be more hittable and not so much a counter-puncher,” said Roach in ESPN.

Both Marquez and Pacquiao vowed to win by knockout on their fourth faceoff on December 8 after figuring in three-close fights.

But the pressure of winning bears heavily on Pacquiao, who wants to erase doubts on his two victories over the Mexican.

"[Marquez] lost those fights and I still had Manny winning by a little bit. Manny started well and he finished well," Roach said. "A lot of fans thought that we lost [the third] fight so we have to redeem ourselves."